Method and apparatus for producing continuous extrusion molding

ABSTRACT

A molding machine for producing a continuous extrusion molding product with varying profile includes a die with an inlet for receiving molten material, a channel, an outlet, and shaping knives rotatable around axes non-parallel to the flow direction of the molten material between first and second operational positions. Shaping knives have molding surfaces and together define a first contour in the outlet when the shaping knives are in their first operational positions, and define a second contour in the outlet when the shaping knives are in their second operational positions. Shaping knives can be rotated around axes perpendicular or oblique to the flow direction of molten material.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention is directed to a method and apparatus forproducing a continuous extrusion molding product with a varying profile.More particularly, the present invention is directed to a moldingmachine having shaping knives rotatable around axes substantiallynon-parallel to the flow direction of the extruded material.

[0003] 2. Description of the Related Art

[0004] Molding products are useful for sealing spaces between, forexample, the edge of a windshield and the body panel of a vehicle. Inthe case of automobile windshield molding, it is well known in the artthat varying the profile of a molding strip along its length can obtainvarious advantages, for example the formation of water-draining channelsfor receiving water flowing on the surface of the windshield. Numerousdesigns for automobile windshield molding strips with a varying profilehave been proposed.

[0005]FIGS. 1 and 2 illustrate one example of a molding strip with avarying profile for sealing the space between a windshield and anopening in the frame of a vehicle body. Molding strip 2 is a continuousplastic strip comprising three sections: an upper section 2A mountedbetween the upper edge of the windshield 11 and the roof panel 12, aside section 2C mounted between the side edges of windshield 11 and thepillar panels 13, and corner sections 2B joining the upper section 2Awith side sections 2C at the corners of windshield 11. Molding strip 2comprises exterior wing 21 including an inward wing portion 21 a and anoutward wing portion 21 b, connecting portion 22, and foot 24.

[0006] Outward wing portion 21 b is for covering the periphery of thevehicle body panels 12, 13 and is of uniform thickness along its length.As illustrated in FIG. 2, the profile of molding strip 2 varies alongthe length of side section 2C such that inward wing portion 21 agradually thickens from corner section 2B to the central portion of sidesection 2C. As inward wing 21 a thickens, connecting portion 22lengthens and sub-inward wing 21 c diverges from inward wing 21 a toform water drain channel 28. Water drain channel 28 gradually widens anddeepens towards the center of side section 2C and then gradually becomesthinner and shallower towards the lower extreme of side section 2C. Theprofile of corner section 2B is the same as that of upper molding 2A;the flexible quality of molding 2 allows it to be deformed and fittedaround the corner of windshield 11. Metal wire 23 is embedded in moldingstrip 2 to reinforce the strip.

[0007]FIG. 3A shows a cross-sectional view of molding strip 2 installedbetween windshield 11 and roof panel 12. FIG. 3B shows a cross-sectionalview of molding strip 2 installed between windshield 11 and a centralportion of pillar panel 13. In FIG. 3A, the windshield 11 is receivedbetween foot 24 and inward wing 21 a. In FIG. 3B, connecting portion 22is lengthened and windshield 11 is received between sub-inward wing 21 cand foot 24. A water drain channel 28 is formed between inward wing 21 aand sub-inward wing 21 c.

[0008]FIGS. 4 and 5 illustrate a prior art molding machine 3 forproducing the molding strip 2. Molding machine 3 comprises die 31 andshaping knives 32 and 33. In FIGS. 4 and 5, plastic material to beextruded flows in a direction perpendicular to the plane of theillustrations. Die 31 is stationary and has an opening 34 in the shapeof a vertically long rectangle, where the upper portion of the rectanglecorresponds to the cross-sectional profile of exterior wing 21.Specifically, the contour of portion 341 corresponds to thecross-sectional profile of outward wing 21 b, the contour of portion 343corresponds to the cross-sectional profile of inward wing 21 a, and thecontour of portion 345 corresponds to the cross-sectional shape ofsub-inward wing 21 c.

[0009] Shaping knives 32, 33 are rectangular plates supported by guides32 a and 32 b, respectively, and are movable in the plane of theillustration, e.g., movable in a plane perpendicular to the flowdirection of the plastic material to be extruded. Shaping knife 32 hasan opening 35 with a contour corresponding to the cross-sectionalprofile of foot 24. When in a first operational position illustrated inFIG. 4, shaping knife 32 is positioned on die 31 such that the openings34, 35 are in the cross-sectional shape of molding strip 2 before inwardwing 21 a is thickened. As the plastic material is extruded, shaft 32 dconnected to a converter 32 b and motor 32 c gradually moves shapingknife 32 to a second operational position illustrated in FIG. 5 suchthat inward wing 21 a is thickened. A reciprocal motion is performed tocause inward wing 21 a to become gradually thinner.

[0010] Shaping knife 33 has a slanted edge 331 with a contourcorresponding to the cross-sectional profile of water drain channel 28.When in a first operational position illustrated in FIG. 4, shapingknife 33 is positioned outside of the flow of the plastic material. Asthe plastic material is extruded, shaft 33 d connected to a converter 33b and motor 33 c gradually moves shaping knife 32 to a secondoperational position illustrated in FIG. 5 such that water drain channel28 is formed. A reciprocal motion is performed to cause water drainchannel 28 to become gradually less deep and thinner.

[0011]FIG. 6 illustrates another molding machine 100 of the prior art inwhich die 104 rotates about pin 103 in a plane perpendicular to the flowof the plastic material to be extruded such that the cross-sectionalshape of opening 104 a is changed during extrusion of the plasticmaterial.

[0012] The molding machines of the prior art are able to produce moldingproducts with varying profiles. However, because the movement of thedies is in a plane perpendicular to the flow of the plastic material,the streamlines of the flow of the plastic material around the edges ofthe dies are significantly disrupted, thereby causing wrinkles on thefinal product. Furthermore, sudden pressure changes in the portions ofthe flow may result in stagnation points where plastic material istrapped and hardened. This also results in wrinkles and even burrs onthe final product. Finally, the movement of the dies between operationalpositions in the molding machines of the prior art causes a suddenincrease in flow pressure against the dies. As a result, the parts ofthe molding machine suffer fatigue and wear-and-tear.

SUMMARY OF THE INVENTION

[0013] It is therefore an object of this invention to provide a methodand apparatus for producing a continuous extrusion molding product witha varying profile, in which the molding machine has shaping knivesrotatable around axes substantially non-parallel to the flow directionof the molten material to be extruded.

[0014] It is another object of this invention to provide a method andapparatus for producing a continuous extrusion molding product with avarying profile, in which the rotation of shaping knives around axesperpendicular or oblique to the flow direction of the molten material tobe extruded allows the contour of the opening between the dies to bemanipulated across a gradient of shapes and sizes to produce a smoothchange in profile of the molded product.

[0015] It is yet another object of the invention to provide a method andapparatus for producing a continuous extrusion molding product with avarying profile, in which disruption of the flow and sudden pressurechanges in portions thereof caused by the movement of shaping knives issignificantly reduced, thereby reducing wrinkles and burrs on the finalproduct.

[0016] According to a first aspect of the present invention, there isprovided a molding machine for producing a molding product with varyingprofile comprising: a die with an inlet for receiving molten material, achannel, and an outlet, the channel directing the molten material fromthe inlet to the outlet along a first axis; a first shaping knife,rotatable around a second axis non-parallel to the first axis between afirst operational position and a second operational position, theshaping knife having a first molding surface; and a second shapingknife, rotatable around a third axis non-parallel to the first axisbetween a first operational position and a second operational position,the shaping knife having a second molding surface; whereby the first andsecond molding surfaces together define a first contour in the outletwhen the first and second shaping knives are in their first operationalpositions, and define a second contour in the outlet when the first andsecond shaping knives are in their second operational positions. In apreferred embodiment, the shaping knife is rotatable around an axisperpendicular to the first axis while the shaping knife is rotatablearound an axis oblique to the first axis. Both shaping knives haveleading edges which are wedge shaped to more easily cut into the flow ofmolten material. Molding surfaces may also be provided in the outlet.

[0017] In the preferred embodiment, the molding product is automobilewindshield molding have an outer wing portion, an inner wing portion, aconnecting portion and a foot. the profile of the inner wing portionvaries between a first profile in which in the inner wing portion has afirst thickness and a second profile in which the inner wing portion hasa second thickness thicker than the first thickness. A water channel isformed in the inner wing portion of the second profile. Generally, thecontour of the first molding surface corresponds to the profile of thefoot, the contour of the second molding surface corresponds to theprofile of the water drain channel, and the contour of the moldingsurface on the outlet corresponds to the outer wing. When the first andsecond shaping knives are in their first operational positions, thecontour of the outlet corresponds to the first profile, and when thefirst and second shaping knives are in their second operationalpositions, the contour of the of the outlet corresponds to the secondprofile.

[0018] According to a second aspect of the present invention there isprovided a method of producing a continuous extrusion molding productincluding the steps of: extruding molten material though an opening in adie when first and second shaping knives are in a first operationalposition together defining a first contour in the opening to form amolding product with a first profile; and gradually rotating the firstshaping knife about a first axis perpendicular to the flow direction ofthe molten material to a second operational position and graduallyrotating the second shaping knife about an axis oblique to the flowdirection of the molten material to a second operational position, thesecond operational positions of the first and second shaping knivesdefining a second contour in the opening, to alter the profile of themolding product across a gradient range of intermediate profiles to asecond profile. The molten material is thermoplastic resin, elastomer,or foam resin. An additional step of rotating the first and secondshaping knives from their second operational positions to the firstoperational positions may also be performed.

[0019] The method and apparatus of the present invention is suitable formolding any molding product with a profile that varies along its length.Examples of molding products for which the method and apparatus of thepresent invention is suitable are automobile windshield molding, plasticrope and mats, and architectural frame molding.

[0020] In the molding machine of the present invention, the shapingknives are rotated about axes perpendicular or oblique flow to the flowdirection of the molten material to be extruded; thus, the intrusion ofthe shaping knives into the flow of molten material is smoother thanthat of the dies of the prior art. As a result, the disruption of thestreamlines of the flow of the molten material around the edges of thedies is significantly reduced, thereby reducing or even eliminatingwrinkles on the final product. This effect can be enhanced by usingshaping knives with leading edges having a wedged profile.

[0021] In addition, sudden pressure changes in the portions of the flowresulting in stagnation points in the flow are avoided, therebyeliminating the problem of molten material being trapped and hardened inthe molding machine of the present invention.

[0022] Finally, because the movement of the shaping knives betweenoperational positions cuts into the flow of molten material in a smoothfashion, there is no sudden increase in flow pressure against theshaping knives. As a result, the parts of the molding machine sufferless fatigue and wear-and-tear than those in the prior art.

BRIEF DESCRIPTION OF DRAWINGS

[0023] The following detailed description, given by way of examples andnot intended to limit the invention to the embodiments described herein,will best be understood in conjunction with the accompanying drawings,in which:

[0024]FIGS. 1 and 2 illustrate an example of automobile windshieldmolding;

[0025]FIGS. 3A and 3B show cross-sectional views of the automobilewindshield molding shown in FIGS. 1 and 2 installed between a windshieldand the frame of a vehicle;

[0026]FIG. 4 illustrates a first molding machine of the prior art withthe dies in a first operational position;

[0027]FIG. 5 illustrates a first molding machine of the prior art withthe dies in a second operational position,

[0028]FIG. 6 illustrates a second molding machine of the prior art;

[0029]FIG. 7A illustrates automobile window molding of the presentinvention installed on the windshield of a car;

[0030]FIG. 7B illustrates the automobile window molding of the presentinvention;

[0031]FIGS. 8A and 8B show cross-sectional views of the automobilewindshield molding shown in FIG. 7 installed between a windshield andthe frame of a vehicle;

[0032]FIG. 9A illustrates the first shaping knife of the presentinvention in the X-Z plane;

[0033]FIG. 9B illustrates the second shaping knife of the presentinvention in the X-Z plane

[0034]FIG. 10A shows a cross-sectional view of the first operationalposition of the first shaping knife in the X-Y plane;

[0035]FIG. 10B shows a cross-sectional view of the first operationalposition of the second shaping knife;

[0036]FIG. 10C shows a cross-sectional view of the molding machine ofthe present invention in the X-Z plane with the first and second shapingknives in a first operational position;

[0037]FIG. 10D shows a profile of the extrudate of the molding machineof the present invention when the shaping knives are in a firstoperational position;

[0038]FIG. 11A shows a cross-sectional view of the second operationalposition of the first shaping knife in the X-Y plane;

[0039]FIG. 11B shows a cross-sectional view of the second operationalposition of the second shaping knife;

[0040]FIG. 11C shows a cross-sectional view of the molding machine ofthe present invention in the X-Z plane with the first and second shapingknives in a second operational position;

[0041]FIG. 11D shows a profile of the extrudate of the molding machineof the present invention when the shaping knives are in a secondoperational position;

[0042]FIG. 12A shows a close-up of the extrusion outlet in the X-Z planewhen the first and second shaping knives are in a first operationalposition; and

[0043]FIG. 12B shows a close-up of the extrusion outlet in the X-Z planewhen the first and second shaping knives are in a second operationalposition.

DETAILED DESCRIPTION OF THE INVENTION

[0044] A preferred embodiment of the present invention discloses amethod and apparatus for producing automobile window molding 20 shown inFIG. 7. It is understood that this embodiment is for illustrativepurposes only. The method and apparatus of the present invention isequally suitable for producing any continuous extrusion molding productwith a varying profile, including automobile window molding with otherspecifications, plastic rope, and architectural frame molding.

[0045] As shown in FIGS. 7A and 7B, a molding strip 20 is a continuousplastic strip comprising three sections: an upper section 20A mountedbetween the upper edge of the windshield 11 and the roof panel 12, aside section 20C mounted between the side edges of windshield 11 and thepillar panels 13, and corner sections 20B joining the upper section 20Awith side sections 20C at the corners of windshield 11. Molding strip 20comprises exterior wing 210 including an inward wing portion 210 a andan outward wing portion 210 b, connecting portion 220, and foot 240.

[0046] Outward wing portion 210 b is for covering the periphery of thevehicle body panels 12, 13 and is of uniform thickness along its length.The profile of molding strip 20 varies along the length of side section20C such that inward wing portion 210 a gradually thickens from cornersection 20B to the central portion of side section 20C. As inward wing210 a thickens, connecting portion 220 lengthens and sub-inward wing 210c diverges from inward wing 210 a to form water drain channel 280. Waterdrain channel 280 gradually widens and deepens towards the center ofside section 20C and then gradually becomes thinner and shallowertowards the lower extreme of side section 20C. The profile of cornersection 20B is the same as that of upper molding 20A; the flexiblequality of molding 20 allows it to be deformed and fitted around thecorner of windshield 11. Metal wires 230 are embedded in molding strip20 to reinforce the strip and provide length guidance during themanufacturing process.

[0047]FIG. 8A shows a cross-sectional view of molding strip 20 installedbetween windshield 11 and roof-panel 12. FIG. 8B shows a cross-sectionalview of molding strip 20 installed between windshield 11 and a centralportion of pillar panel 13. In FIG. 8A, the windshield 11 is receivedbetween foot 240 and inward wing 210 a. In FIG. 8B, connecting portion220 is lengthened and windshield 11 is received between sub-inward wing210 c and foot 240. A water drain channel 280 is formed between inwardwing 210 a and sub-inward wing 210 c.

[0048]FIG. 9A shows a shaping knife 82 of the present invention in theX-Z plane. Shaping knife 82 is generally planar in shape and comprisesannular portion 823 at the distal end provided with a hole 825H, leadingedge 820 and molding surfaces 821. Molding surfaces 821 traverse theshaping knife 82 longitudinally at a skewed angle such that trench 822is cut across a corner of the knife to distal end 824. The contour oftrench 822 at distal end 824 corresponds to the cross-sectional profileof foot 240. Leading edge 820 preferably offers a wedged profile. A pin825 is received in hole 825H such that shaping knife 82 can rotate aboutthe a-a axis, which in this illustration corresponds to the Z-axis.Thus, it is understood that shaping knife 82 rotates about an axisperpendicular to the flow direction of the molten material.

[0049]FIG. 9B shows a shaping knife 83 of the present invention in theX-Z plane. Shaping knife 83 is generally planar and comprises annularportion 833 provided with a hole 835H, leading edge 830, molding surface831 and distal end 834. The contour of molding surface 831 correspondsto the cross-sectional profile of channel 280. Leading edge 830preferably offers a wedged profile. A pin 835 is received in hole 835Hsuch that shaping knife 83 can rotate about the b-b axis. The b-b axisis oblique to the flow direction of the molten material.

[0050]FIGS. 10A-10C, 11A-11C and 12A-12B illustrate a molding machine 40according to the preferred embodiment of the present invention. Moldingmachine 40 comprises a die 400 including inlet 410 and outlet 420connected by channel 430, shaping knife 82 rotatably disposed on pin825, shaping knife 83 rotatably disposed on pin 835, driving unit 450connected to the shaping knife 82 via connector 455, and driving unit550 connected to the shaping knife 83 via connector 555. Driving units450 and 550, for example pistons or motors with converters, are fordriving shaping knives 82, 83 to rotate around their respective pinsbetween first and second operational positions, as described in detailbelow. FIGS. 12A and 12B show a close-up of outlet 420 and the proximalends 824, 834 of shaping knives 82, 83 in the X-Z plane. Outlet 420 isan extrusion opening including molding surface 421 with a contourcorresponding to the profile of wing 210 and molding surface 422 with acontour corresponding to the profile of connecting portion 220.

[0051] During the extrusion process, molten material 60 is receivedthrough inlet 410 and extruded from outlet 420. It is thereforeunderstood that the molten material travels through channel 430 in adirection substantially parallel to the Y-axis, as indicated by thearrows in FIGS. 10A and 11A. Examples of molten material suitableinclude thermoplastic resin (for e.g., PVC, PE, PP, MCOC, Nylon, EVA,NBR), elastomer (e.g., TPE, TPU, TPO, rubber) and foam resin. A singlemolten material can be used in the fabrication of molding 20.Alternately, two or more materials can be applied to form a compositestructure. Shaping knives 82, 83 are rotatable between first and secondoperational positions such that their molding surfaces; in conjunctionwith the molding surfaces 421, 422 of outlet 420, define two differentcontours, the first corresponding to the molding strip before the inwardwing portion 210 a thickens, e.g., the profile of the molding strip insections 20A, 20B and the extreme ends of 20C, as illustrated in FIG.10D, and the second corresponding to the profile of the molding strip 20at the center of the side section 20C, as illustrated in FIG. 11D. It isunderstood, however, that a gradient range of intermediate contoursexists between the first and second operational positions, and theseintermediate profiles can be manipulated by modifying the disposition ofthe molding surfaces 821 and 831, as well as the speed of rotation andpressure of the molten material 60, so as to obtain an extrudate with aprofile that varies across a gradient range of intermediate profiles.

[0052]FIGS. 10A, 10C and 12A illustrate the position of shaping knife 82when in the first operational position. Namely, the shaping knife ispositioned such that a greater portion of the knife is in channel 430and molding surfaces 821 are in a first position. FIGS. 10B, 10C and 12Aillustrate the position of shaping knife 83 when in the firstoperational position. Namely, the shaping knife is positioned such thatthe knife does not enter channel 430 and molding surface 831 is outsidechannel 430. FIGS. 11A, 11C and 12B illustrate the position of shapingknife 82 when in the second operational position in which a lesserportion of the knife is in channel 430 and molding surfaces 821 are in asecond position. FIGS. 11B, 11C and 12B illustrate the position ofshaping knife 83 with in the second operational positioning which theshaping is positioned with molding surface 831 in channel 430. Shapingknives 82, 83 can be reciprocally rotated between the first and secondoperational positions.

[0053] It is noted that shaping knife 82 is rotated about an axisperpendicular to the flow direction of molten material 60. Thus, whenshaping knife 82 is rotated from the second operational position to thefirst operational position, the wedged profile of leading edge 820 cutsinto the flow and directs it through the trench 822 formed by moldingsurfaces 821 with minimum disruption of the streamlines of the flow.Furthermore, when shaping knife 82 is rotated back into the secondoperational position, the wedged profile of leading edge 820 againallows smooth transition of the flow through molding surfaces 821 duringrotation.

[0054] Similarly, shaping knife 83 is rotated about an axis oblique tothe flow direction of molten material 60. When shaping knife 83 isrotated from the first operational position to the second operationalposition, the wedged profile of leading edge 830 cuts into the flow anddirects it around molding surface 831 with minimum disruption of thestreamlines of the flow. When shaping knife 83 is rotated back out ofthe flow into the first operational position, the wedged profile ofleading edge 830 again allows smooth transition of the flow aroundmolding surfaces 831 during rotation.

[0055] The following discussion explains the method of producingautomobile windshield molding using the molding machine 40 describedabove.

[0056] Automobile windshield molding 20 is extruded as a single moldingbeginning with side section 20C, the proceeding with corner section 20B,upper section 20A, a second corner section 20B and a second side section20C.

[0057] When side section 20C is first extruded, shaping knives 82 and 83are set in their first operational positions as illustrated in FIGS.10A-10C, such that taken together with molding surfaces 421, 422, thecontour of outlet 410 is that illustrated in FIG. 12A corresponding tothe profile of the automobile windshield molding 20 before the inwardwing portion 210 a is thickened. Metal wires 230 are fed in togetherwith molten material 60 into inlet 410 and passed through channel 430 tooutlet 420 such that molding 20 has the profile illustrated in FIG. 10D,e.g., the profile of the automobile windshield molding 20 before theinward wing portion 210 a is thickened, is extruded. Metal wires 23serve to reinforce the extrudate. Furthermore, metal wires 23 can beused to pull or draw out hardened extrudate and measure the length ofthe molding extruded. Metal foil or other suitable non-melting materialmay also be used.

[0058] After the side section 20C has been extruded for a certain lengthwith the profile illustrated in FIG. 10D, shaping knives 82 and 83 arerotated to their second operational positions. It is understood thatthis rotation is gradual, allowing for a gradient change in the profileof the extrudate. Namely, as shaping knife 82 is rotated outwardly,leading edge 820 and molding surfaces 821 shift in position such thatopening 420 gradually passes through a number of intermediary contoursto that illustrated in FIG. 12B, viz. connecting edge 220 is elongatedwhile foot 240 maintains its position at the end of the connecting edge220 such that inward wing portion 210 a is thickened. Similarly, asshaping knife 83 is rotated inwardly, leading edge 830 and moldingsurface 831 cut into the flow of molten material 60 such that opening420 gradually passes through a number of intermediary contours to thatillustrated in FIG. 12B, viz. a channel 280 is gradually cut into thethickening inward wing 210 a, thereby dividing off sub-inward wing 210 cfrom inward wing 210 a. FIG. 11D shows a cross-sectional view of theextrudate when shaping knives 82 and 83 have reached their secondoperational positions, e.g., an extrudate with a profile of that of theautomobile molding 20 at the center of side section 20C.

[0059] After the side section 20C has been extruded for a certain lengthwith the profile illustrated in FIG. 11D, shaping knives 82 and 83 arerotated back to their first operational positions. As before, it isunderstood that this rotation is gradual, allowing for a gradient changein the profile of the extrudate. Namely, as shaping knife 82 is rotatedinwardly, leading edge 820 and molding surfaces 821 shift in positionsuch that opening 420 gradually passes back through a number ofintermediary contours to that illustrated in FIG. 12A, viz. connectingedge 220 is shortened while foot 240 maintains its position at the endof the connecting edge 220 such that inward wing portion 210 a becomesthinner. Similarly, as shaping knife 83 is rotated outwardly, leadingedge 830 and molding surface 831 are removed from the flow of moltenmaterial 60 such that the profile of opening 420 gradually moves througha number of intermediary profiles to that illustrated in FIG. 12A, viz.the channel 280 gradually grows less deep and thinner until it inwardwing 210 a and sub-inward wing 210 c merge and the channel 280disappears. The molding 20 is then extruded for a certain length withthe opening 420 having the profile illustrated in FIG. 12A correspondingto the upper extreme of side section 20C, the corner section 20B, theupper section 20A, the second corner section 20B, and the upper extremeof side section 20C.

[0060] To form the second side section 20C with a varying profile, theprocess describe above is repeated. Shaping knives 82 and 83 are rotatedfrom their first operational positions to their second operationalpositions to form the center part of side section 20C, and then backagain to their first operational positions to form the lower extreme ofside section 20C.

[0061] While the invention has been described with reference to variousillustrative embodiments, the description is not intended to beconstrued in a limiting sense. Various modifications of the illustrativeembodiments, as well as other embodiments of the invention, will beapparent to those person skilled in the art upon reference to thisdescription. For example, the use of one shaping knife or three or moreshaping knives is equally suited to production of a molding product withvarying profile according to the present invention. The shapes of themolding surfaces and the axes of rotation may also be altered to suitthe desired profile of the extrudate.

[0062] It is therefore contemplated that the appended claims will coverany such modifications or embodiments as may fall within the scope ofthe invention defined by the following claims and their equivalents.

What is claimed is:
 1. A molding machine for producing a continuousextrusion molding product with varying profile comprising: a die with aninlet for receiving molten material, a channel, and an outlet, thechannel directing the molten material from the inlet to the outlet alonga first axis; and at least one shaping knife, rotatable around a secondaxis non-parallel to the first axis between a first operational positionand a second operational position, the shaping knife having a firstmolding surface which defines a first contour in the outlet when in theshaping knife is in the first operational position, and defines a secondcontour in the outlet when the shaping knife is in the secondoperational position.
 2. The molding machine as claimed in claim 1,wherein the shaping knife is rotatable around an axis perpendicular tothe first axis.
 3. The molding machine as claimed in claim 1, whereinthe shaping knife is rotatable around an axis oblique to the first axis.4. The molding machine as claimed in claim 1, wherein the shaping knifehas a leading edge which is wedge shaped.
 5. The molding machine asclaimed in claim 1, wherein the out-let comprises a second moldingsurface.
 6. A molding machine for producing a continuous extrusionmolding product with varying profile comprising: a die with an inlet forreceiving molten material, a channel, and an outlet, the channeldirecting the molten material from the inlet to the outlet along a firstaxis; and a first shaping knife, rotatable around a second axisnon-parallel to the first axis between a first operational position anda second operational position, the shaping knife having a first moldingsurface; and a second shaping knife, rotatable around a third axisnon-parallel to the first axis between a first operational position anda second operational position, the shaping knife having a second moldingsurface; whereby the first and second molding surfaces together define afirst contour in the outlet when the first and second shaping knives arein their first operational positions, and define a second contour in theoutlet when the first and second shaping knives are in their secondoperational positions.
 7. The molding machine as claimed in claim 1,wherein the shaping knife is rotatable around an axis perpendicular tothe first axis.
 8. The molding machine as claimed in claim 1, whereinthe shaping knife is rotatable around an axis oblique to the first axis.9. The molding machine as claimed in claim 1, wherein the shaping knifehas a leading edge which is wedge shaped.
 10. The molding machine asclaimed in claim 1, wherein the outlet comprises a third moldingsurface.
 11. The molding machine as claimed in claim 10, wherein themolding product is automobile windshield molding have an outer wingportion, an inner wing portion, and a foot, the profile of the innerwing portion varying between a first profile in which in the inner wingportion has a first thickness and a second profile in which the innerwing portion has a second thickness thicker than the first thickness, awater channel being formed in the inner wing portion of the secondprofile, wherein: the contour of the first molding surface correspondsto the profile of the foot; the contour of the second molding surfacecorresponds to the profile of the water drain channel; and the contourof the third mol ding surface corresponds to the outer wing; wherein thecontour of the outlet when the first and second shaping knives are intheir first operational positions corresponds to the first profile; andthe contour of the of the outlet when the first and second shapingknives are in their second operational positions corresponds to thesecond profile.
 12. A method for producing a continuous extrusionmolding product with varying profile using a molding machine comprisinga die and at least one shaping knife comprising the steps of: extrudingmolten material though an opening in the die when the shaping knife isin a first operational position defining a first contour in the openingto form a molding product with a first profile; and gradually rotatingthe shaping knife about an axis non-parallel to the flow direction ofthe molten material to a second operational position defining a secondcontour in the opening to alter the profile of the molding productacross a gradient range of intermediate profiles to a second profile.13. The method as claimed in claim 12, wherein the molten material isthermoplastic resin, elastomer, or foam resin.
 14. The method as claimedin claim 12, wherein the shaping knife is rotated around an axisperpendicular to the plane containing the first axis.
 15. The method asclaimed in claim 12, wherein the shaping knife is rotated around an axisoblique to the plane containing the first axis.
 16. The method asclaimed in claim 12, wherein the shaping knife has a leading edge whichis wedge shaped, and when the shaping knife is rotated from the firstoperational position to the second operational position, the wedge cutsinto the flow of molten material.
 17. The method as claimed in claim 12,further comprising the step of rotating the shaping knife from thesecond operational position to the first operational position.
 18. Amethod for producing a continuous extrusion molding product with varyingprofile using a molding machine comprising a die, a first shaping knifeand a second shaping knife comprising the steps of: extruding moltenmaterial though an opening in the die when the first and second shapingknives are in a first operational position together defining a firstcontour in the opening to form a molding product with a first profile;and gradually rotating the first shaping knife about a first axisperpendicular to the flow direction of the molten material to a secondoperational position and gradually rotating the second shaping knifeabout an axis oblique to the flow direction of the molten material to asecond operational position, the second operational positions of thefirst and second shaping knives defining a second contour in theopening, to alter the profile of the molding product across a gradientrange of intermediate profiles to a second profile.
 19. The method asclaimed in claim 18, wherein the molten material is thermoplastic resin,elastomer, or foam resin.
 20. The method as claimed in claim 18, whereinthe first and second shaping knives each have a leading edge which iswedge shaped for cutting into the flow of molten material.
 21. Themethod as claimed in claim 18, further comprising the step of rotatingthe first and second shaping knives from their second operationalpositions to the first operational positions.